Plaiting



E. E. RHODES 3,318,128

May 9, 1967 PLAITING 4 Sheets-Sheet 1 Filed April 15, 1964 mvn Al 'Anmurll EUGENE E RHODES INVENTOR.

ATTORNEYS E.. E. RHODES May 9, 1967 PLAITING 4 Sheets-Sheet 2 Filed April 15, 1964 INVENTOR.

EUGENE E. RHODES A TTO/PNEVS y 9, 1967 E. E. RHODES 3,318,128

PLAITING Filed April 15, 1964 4 Sheets-Sheet 3 EUGENE E. RHODES INVENTOR.

BY 6 3 m ATTORNEYS E- E. RHODES May 9, 1967 PLAITING 4 Sheets-Sheet 4 Filed April 15, 1964 UGENE E. RHODES INVENTOR.

ATTORNEYS United States Patent 3,318,128 PLAITING Eugene E. Rhodes, Believille, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Filed Apr. 15, 1964, Ser. No. 359,986 8 Claims. (Cl. 72--187) This invention relates to the art of plaiting. In particular, this invention is concerned with a method and means for forming even convolutions in a deformable sheet material. More particularly, this invention is concerned with plaiting relatively thin metal strips having regularly spaced, preformed deformations.

The method and means of this invention may be used to plait any suitably deformable material which retains the configuration of deformation until acted upon by a significant exterior force. Plaits thus formed may be used in a variety of applications, e.g. as spacers, ventilator elements, decorative trim, heat exchange elements, etc. This invention is hereinafter described in detail with relation to its used in the manufacture of heat exchange elements for use in automobile radiators.

Although details of construction may vary, an engine cooling radiator ordinarily includes an inlet tank and an outlet tank for suitable connection with the water jacket of the engine, and a core or heat dissipating unit interposed between two tanks for the travel of water in thin streams from one tank to the other through a number of spaced passageways or water tubes of suitable heat exchange material. Between each pair of these water conduits flows an air stream to take up or absorb heat carried by the water. A heat exchange fin strip or spacer element is generally folded back and forth and interposed between the water tubes for cooperation therewith to divide the intervening space into a number of small air cells.

Ordinarily, the opposite edges or front and rear faces of the core assembly are dipped first in a flux and then in molten solder to seal the margins of the walls of the water tubes where necessary and to join the fin strips to the walls. If the water tubes and fin strips are evenly formed so as to make possible continuous contact from edge to edge, there will be an inward capillary flow of solder toward the center of the core and a positive bond will result throughout substantially the entire depth of the core to insure the free flow of heat into the fins.

It is one object of this invention to provide a method and means for plaiting sheet material so as to form a plurality of even convolutions.

It is another object of this invention to provide method and means for plaiting metal strips having regularly spaced, preformed deformations which leaves such deformations essentially unchanged.

Many other objects and advantages of this invention will be obvious to those skilled in the art from the detailed description which follows when read in conjunction with the accompanying drawings wherein like reference characters indicate like or corresponding parts;

FIGURE 1 is a semidiagrammatic side view of finforming and plaiting apparatus which can be used to form and plait strip material in accordance with this invention;

FIGURE 2 is a perspective view of a radiator fin strip formed in accordance with this invention;

FIGURE 3 is a partial top elevation view of a machine which incorporates the apparatus illustrated in FIGURE .1; portions of the cover of said machine being removed to reveal the placement of the fin-forming unit;

FIGURE 4 is a sectional view taken along line 44 of FIGURE 3;

FIGURE 5 is a detailed view of the paired plaiting elements of FIGURE 1 in operational engagement with a section of strip material;

FIGURE 6 is a semidiagrammatic view of the plaiting rolls and strippers of FIGURE 5; and

FIGURE 7 is a diagrammatic assembly view of the drive train of the machine of FIGURE 3.

Referring now to FIGURE 1, a roll 11 supports metal strip stock 13 and is positioned to permit the feeding of strip stock 13 to a roll die 15 which is constructed and arranged to provide strip stock 13 with regularly spaced deformations and to initiate the bending of the strip stock in-to evenly spaced convolutions. Strip stock 13 may be of any suitable metal or alloy having good heat exchange characteristics, e.g. copper, aluminum, brass, etc. Roll die 15 comprises a pair of matched fin-forming rolls 17 and 19 each of which comprise a plurality of abutting gearlike wheels or blades which in operational position are in mes-h with the corresponding wheels or blades of the companion roll upon the strip stock passing therebetween.

A variety of devices have been designed for providing regularly spaced impressions upon a strip material and/ or plaiting such material to form alternately reversed folds of even length. Typical of these are the devices illustrated and/or described in US. Patents 1,012,568, 1,148,670, 1,212,482, 1,617,163, 1,640,147, 1,937,466, 2,141,235, 2,252,209, 2,329,789, 2,443,377, 2,483,694, 2,035,408 and 3,083,662.

The construction of one such roll die is described in detail in my copending application, Ser. No. 259,547, which is incorporated herein by reference.

The fin strip shown in FIGURE 2 is of folded or corrugated outline providing a series of planar based fins 16 between folds or curved connecting members 18. A typical strip material is about .003 inch in thickness. Each fin has a plurality of slits with metal adjacent each slit turned out of the base plane of the fin to provide each fin with a plurality of louvered Windows 17. Such deformations are designedly provided to assist in the control and direction of air flow through the radiator core. In the plaiting of such strips the alignment of such louvers, or other deformation as the case may he, must be maintained if the fin strip is to function in the intended manner in a radiator assembly.

After passing between rolls 17 and 19 the now facially deformed, partially folded strip 13 passes over a platen or table 21 and is engaged by the teeth of a star-wheel impeller 23. Impeller 23 may comprise two or more tooth bearing wheels 25 in parallel relationship which are spaced apart so as to engage and exert force against portions of each fin which are located between or to the side of the aforementioned louvers or other deformations. A top View of impeller 23 is provided in FIGURE 3. Impeller 23 forces partially folded strip 13 against and eventually through a spring actuated restrictor 31. Restrictor 31 comprises a bracket support post 33 which in turn is supported by platen 21. A horizontally positioned pivot pin 35 is rigidly affixed to post 33 and pivotally supports bracket 37 Pivotally secured to bracket 37 by pivot pin 39 is upper shoe 41. Bracket 37 is under a downward directed pressure exerted by spring 43 which has one end resting within a cylindrical depression 45 in bracket 37 and the opposite end aflixed to bracket 47 which in turn has one end connected to the top of post 33 and has a spring 49 interposed therebetween. Bracket 47 is provided with a wing nut assembly 51 for adjusting the pressure of spring 43 against bracket 33. Lower shoe 55 extends through an opening in platform 21 and is under constant pressure from spring 57 which is supported by rod 59. Rod 59 in turn is supported by platen 21.

The spring 43 is adjusted to provide the desired amount of resistance to the passage of partially folded strip 13 between upper shoe 41 and lower shoe 55. Impeller 23 engages and forces the partially folded strip 13 into the mouth of the passageway between upper shoe 41 and lower shoe 55 and hence into contact with upper shoe 41 and lower shoe 55. The folds in strip 13 become more accentuated as pressure is built up by the constant feed of strip material by impeller 23 which eventually creates a wedging pressure that is sufiicient to overcome the pressure exerted against the strip by springs 43 and 57 with a release of a section of strip 13. When the pressure from the build-up of strip 13 between impeller 23 and restrictor 31 is released, springs 43 and 57 again restrict further movement of strip 13 between the upper and lower shoes until such build-up is repeated. In the course of building up sufiicient pressure to force the upper and lower shoes apart the folding of strip 13, initiated by rolls 17 and 19, is increased. This method of plaiting or gathering of strip material is known to the art and if employed as the sole means of plaiting tends to disadvantageously distort the fin strip because of the pressure required to effect a sufficient bending of the metal strip into the desired folds or corrugations. In accordance with this invention it is preferred to retain restrictor 31 in the system but to reduce the pressure required to effect a release of strip material from between upper shoe 41 and lower shoe 55. By this method some additional folding deformation is gained without undesirable distortion.

I11 this embodiment the strip passes directly from the spring actuated restrictor 31 to plaiting mechanism 61 which includes plaiting rolls 63 and 65. These rolls are more fully illustrated in FIGURES and 6. In another embodiment, not separately shown, restrictor 31 is eliminated and the partially folded strip is passed directly to rolls 63 and 65.

Rolls 63 and 65 alternately engage alternate and opposite folds of strip 13. The configuration of rolls 63 and 65 in cooperation with the pressures exerted upon strip 13 by their 'counterrotation increase the closure of the partially formed folds while shaping the connecting members 18 to the desired even curvature. In this embodiment roll 65 rotates clockwise while roll 63 rotates counterclockwise.

Rolls 63 and 65 have about their perimeters a plurality of evenly spaced, transversely extending grooves or channels 67 and 69 respectively. Between each pair of adjacent grooves are teeth or lands 66 and 68 respectively, the tips of which are also curved. Rolls 63 and 65 are spaced apart but aligned in a manner such as to mesh if brought into contact by vertical displacement, ie, the teeth or lands thereof are maintained out of interdigital relationship as illustrated in FIGURES 1 and 5 but aligned to admit of interdigitation if said rolls were to be moved towards each other while maintaining such alignment. In other words when one of the teeth or lands 68 of roll 65 is nearest to roll 63, a longitudinal bisector of such tooth and transverse bisector of such roll is in line with the corresponding bisector of one of the grooves or channels 67 of roll 63.

The lands or teeth 66 and 68 upon engaging one of the partial folds of strip 13 provide line contact across the full width of strip 13 and impel the strip between the counter-rotating rolls 63 and 65. The placement and configuration of the lands and grooves on rolls 63 and 65 assist in the proper positioning of the partially folded strip for processing in that contact with a fold by a land or tooth of one of the paired rolls assists in guiding the adjacent and opposite fold into a groove of the opposite roll.

The rolls 63 and 65 are spaced apart a distance sufi"1- cient to prevent cooperative pressures from the paired plaiting rolls causing significant deformation of the essentially planar based fins. Preferably, the rolls are aligned and spaced apart in a manner such as to permit such fins to pass between the rolls in substantially parallel relationship with each other. This facet of the spacing can be controlled by controlling the distance between the rolls. In addition, protection of t e fin, e o a qn requires that attention be given to the depth of the grooves 67 and 69 and/ or to the height of the lands or teeth 66 and 68. In the method of this invention only the curved connecting member and that portion of the planar base between the connecting member and the fin deformation comes into contact with the impelling land or tooth. Thus, the facial configuration of the fin is preserved both by avoiding direct contact with the teeth of the plaiting roll and by proper spacing of the plaiting rolls to avoid buckling, jamming, etc.

In this step of plaiting-the grooves between the lands or teeth, more particularly the curved portion between teeth known as the fillet in gear terminology, is shaped to conform to the curved configuration of the intended fold between each pair of louvered fins. The deformable fin strip upon being drawn into such grooves by the action of rolls 63 and 65 may be placed under a pressure sufiicient to cause the partially formed fold to assume the contour of the fillet and insufficient to distort the essentially planar bases of the adjacent fins.

Rolls 63 and 65 are provided with stripper bars 71, 73, 75 and 77 which lie parallel to platen 21 and extend through grooves extending about the perimeters of rolls 63 and 65. Thus, if strip 13 after passing through the zone of greatest restriction between rolls 63 and 65 attempts to cling to one of the rolls it is stripped from such roll by the corresponding strippers.

It is within the scope of this invention to provide a second restrictor similar to or different from restrictor 31 to receive and further compress the plaited material issuing from rolls 63 and 65. In the preferred embodiment, however, the final step of plaiting is effected by rolls 63 and 65.

Referring now to FIGURES 3, 4 and 7, the fin forming and strip plaiting units previously discussed in relation to FIGURES 1, 2, 5 and 6 are shown in assembly in a machine which in addition to such units includes power means and drive train for operating such units in a manner such as to carry out the functions aforedescribed.

A shaft 113 is operatively connected at one end to a conventional electric motor 111 and at the other end to lower drive wheel 115. Lower drive wheel 115 is operatively connected to upper drive wheel 119 via a link belt 117. Upper drive wheel 119 is operatively connected to one end of shaft 125. Shaft supports lower drive gear 126 which is in mesh with upper drive gear 127. Upper drive gear 127 supports one end of shaft 128 to which it is operatively connected. Mounted on and operatively connected to shaft 128 are gear 129, the lower fin-forming roll 19 and gear 141. Gear 129 is in mesh with gear 131 when the strip is being processed. Gear 131 is mounted on and operatively connected to shaft 133 which rides in a bearing, not shown, on the frame of the machine. Mounted on and operatively connected to shaft 133 is the upper fin-forming roll 17. Wheel 135 is representative of vertical adjustment means, not further shown, whereby gear 131, shaft 133 and roll 17 can be raised and lowered to accommodate changes in the thickness of the strip material being processed, etc.

Gear 141 is in mesh with idler gear 143 which in turn is in mesh with gear 145. Gear 145 is mounted on and operatively connected to shaft 147. Mounted on and operatively connected to shaft 147 is impeller 23 previously shown in FIGURE 1. Mounted on and operatively connected to the end of shaft 147 opposite gear 145 is sprocket wheel 149. Sprocket wheel 149 is operatively connected to sprocket wheel 153 by chain 151.

Sprocket wheel 153 is mounted on and operatively connected to shaft 155. Mounted on and operatively connected to shaft 155 are gear 157 and plaiting roll 65. Gear 157 is in mesh with gear 159. Plaiting roll 63 and gear 159 are mounted upon and operatively connected to shaft 161.

As the fin strip is passed from restrictor 31 it is guided to plaiting rolls 63 and 65 by lateral guide members 163 and 165.

Thus, when strip material is fed to fin-forming rolls 17 and 19 and the aforedescribed power train is actuated via motor 111, the strip passes between fin-forming rolls 17 and 19 wherein the desired deformation of the fins is achieved and the folding of the strip between fins is initiated. The partially folded strip is engaged by impeller 23 and pressed against the restrictor 31 until sufficient pressure is provided to effect its release therefrom in the course of which additional closure of the folds is effected.

The partially folded strip is then guided to and engaged by the plaiting rolls 63 and 65 which provides evenly rounded turns in continued folding. The strip upon emerging from rolls 63 and 65 may then be cut to the desired lengths and employed for its intended use.

The term transverse is used herein in relation to the plaiting rolls 63 and 65 to mean transverse to the curved outer surfaces of such rolls.

Having thus described a preferred embodiment of this inveniton with particularity, it becomes obvious that modifications can be made in the same without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. The method of plaiting a preformed strip of deformable sheet material having regularly spaced segments separated by alternately reversed partial folds which comprises introducing said strip between a matched pair of counterrotating rolls each of which have a plurality of transversely extending lands of even profile equally spaced about their perimeters with adjacent lands of each of said rolls separated by transversely extending grooves of even profile, engaging alternate folds of said strip With lands of the first of said rolls, engaging alternate and opposite folds of said strip with lands of the second of said rolls, impelling said strip with said lands of said first and second rolls between said rolls in a manner such that alternate folds of said strip are positioned within grooves of said first roll, opposing folds, of said strip are positioned Within grooves of said second roll, and the cooperative rotational action of said rolls effects additional closure of said folds, said rolls being spaced apart a distance suflicient to prevent significant deformation of said segments by opposing pressures from said rolls and to maintain the lands thereof out of interdigital relationship.

2. The method of claim 1 wherein said matched pair of rolls are of equal diameter, said segments are of essentially even length, and said rolls are rotated at equal peripheral speeds.

3. The method of claim 1 wherein said rolls are aligned in a manner such that a plane bisecting a given roll of said pair and coinciding with the longitudinal axis of a given land thereof will bisect a groove of the companion roll when said land in its rotation reaches the point of minimum distance to said companion roll.

'4. The method of claim 1 wherein said strip after being passed between said rolls is passed into a spring actuated restrictor wherein said strip is compressed and increased closure of said folds is efiected.

5. The method of claim 1 wherein said segments are separated by connecting members having alternately reversed, centrally positioned, folds therein and the cooperative rotational action of said rolls while effecting additional closure of said folds increase the conformation of said connecting members to the configuration of said grooves.

'6. The method of -plaiting a heat exchange element for use in heat exchange with a water pass tube of an automobile radiator which comprises passing a deformable strip of sheet metal between rotating roll dies which initiate folding of said strip at evenly spaced intervals and deform the intervening strip material so as to provide evenly spaced segments having a plurality of dcformations and separated by alternately reversed, partially folded, connecting members and subsequently increasing the closure of the resultant folds of said connecting members by introducing the resultant strip between a matched pair of counterrotating rolls each of which have a plurality of transversely extending grooves of even profile, engaging alternate folds of said strip with lands of the first of said rolls, engaging alternate and opposite folds of said strip with lands of the second of said rolls, impelling said strip with said lands of said first and second rolls between said rolls in a manner such that alternate folds of said strip are positioned within grooves of said first roll, opposing folds of said strips are positioned within grooves of said second roll, and the cooperative rotational action of said rolls effects additional closure of said folds, said rolls being spaced apart a disstance sufiicient to prevent significant deformation of said segments by opposing pressures from said rolls and to maintain the lands thereof out of interdigital relationship.

7. The method of claim 6 wherein said evenly spaced segments each have an essentially planar base with a plurality of slits therein and metal adjacent each slit turned out of the plane of said planar base.

8. The method of claim 6 wherein said strip is passed, prior to introduction between said matched rolls and subsequent to passage between said roll dies, into a spring actuated res-trictor wherein said strip is compressed and increased closure of said folds is effected.

References Cited by the Examiner UNITED STATES PATENTS Re. 2 2,956 6/ 1945 Salzer 72 1 87 1,546,195 7/1925 Briskin 72-487 1,937,466 11/1933 Smith et al. 7 2196 2,071,584 2/1937 Shippy 72-190 3,191,418 6 /1965 Modine 72187 CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner. 

1. THE METHOD OF PLAITING A PREFORMED STRIP OF DEFORMABLE SHEET MATERIAL HAVING REGULARLY SPACED SEGMENTS SEPARATED BY ALTERNATELY REVERSED PARTIAL FOLDS WHICH COMPRISES INTRODUCING SAID STRIP BETWEEN A MATCHED PAIR OF COUNTERROTATING ROLLS EACH OF WHICH HAVE A PLURALITY OF TRANSVERSELY EXTENDING LANDS OF EVEN PROFILE EQUALLY SPACED ABOUT THEIR PERIMETERS WITH ADJACENT LANDS OF EACH OF SAID ROLLS SEPARATED BY TRANSVERSELY EXTENDING GROOVES OF EVEN PROFILE, ENGAGING ALTERNATE FOLDS OF SAID STRIP WITH LANDS OF THE FIRST OF SAID ROLLS, ENGAGING ALTERNATE AND OPPOSITE FOLDS OF SAID STRIP WITH LANDS OF THE SECOND OF SAID ROLLS, 